Static Fracture Behavior of a Ceramic Matrix Composite at Elevated Temperatures
AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING
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This study investigated systematically the damage initiation damage progression, and failure modes of a ceramic matrix composite, NicalonCAS, when loaded in tension at elevated temperatures in the presence of air. A cross-ply lay-up, 090 2s, was studied. The primary means of analysis were stress-strain data taken during monotonic and incremental load tests and crack density assessments. Testing was conducted at room temperature 700 deg C, and 850 deg C. The stress-strain response was consistent for monotonic and incremental loading, except for a decrease in failure load at the elevated temperatures. Initial damage progression was also consistent, but the damage leading to failure and the final failure mode at 850 deg C were different due to the oxidation of the fibers. The oxidation created a brittle interface between the fiber and matrix, which resulted in an increase in fiber pull-out at the failure surface.
- Ceramics, Refractories and Glass